Arsenal's title challenge got off to the worst possible start at the Emirates on Sunday as West Ham sealed a shock 2-0 victory courtesy of goals from Cheikhou Kouyate and Mauro Zarate.

Summer signing Petr Cech was at fault for the Hammers' first after throwing himself at a free-kick and allowing Kouyate to head into an empty net from 10 yards just two minutes before half-time.

Zarate, who spent an unsuccessful loan spell at QPR last season, made things more comfortable for Slaven Bilic's side when he picked up a loose ball and buried a low shot into the bottom corner with 57 minutes on the clock.

Three headers and a chest provided the goals as Southampton and Newcastle exchanged the lead but ended up sharing the honours in their Premier League opener.

Graziano Pelle opened the scoring for Southampton with a towering header from Cedric Soares' cross before Papiss Cisse equalised for Newcastle with his chest before half time.

Newcastle's summer signing from PSV Einhoven Georginio Wijnaldum won the hosts back the lead with another quality header from Gabriel Obertan's cross but it wasn't to last as Saints substitute Shane Long finished off Dusan Tadic's delivery from the right for 2-2 with 10 minutes to go.

There will also be five added minutes at St James' Park. Plenty of time for either Newcastle or Southampton to find a winner...

15:18

Arsenal 0-2 West Ham United

As Giroud scoops another effort wide from an Oxlade-Chamberlain cross, West Ham send on Madibo Maiga for Sakho as five additional minutes are set to be played - much of that due to the Giroud/Tomkins incident.

Arsenal's Olivier Giroud lies on the pitch following a clash of heads with West Ham's James Tomkins

15:17

Arsenal 0-2 West Ham United

West Ham are even starting to show some ambition in attack as they win a corner. Arsenal fans are heading for the exits - they've seen enough of what looks like is going to be a disastrous opening day of the season for their side.

15:13

Arsenal 0-2 West Ham United

Time is running out for Arsenal as West Ham United still hold firm. This has been an amazing display from the Hammers who continue to not just deny the Gunners a way back into this match, but also any attacking flow in their play as Adrian dives low to deny a Cazorla strike.

15:12

Newcastle United 2-2 Southampton

Newcastle had already sent on Aleksandar Mitrovic, booked seconds after coming on for a crunching tackle, for Cisse.

And now Siem de Jong replaces Wijnaldum for Newcastle's final change as they chase a winner.

15:08

GOAL! Newcastle United 2-2 SOUTHAMPTON

It's been coming and Southampton finally get their equaliser with Shane Long jumping highest at the back post to head home with 11 minutes to play for. What a final 10 minutes we have coming up in both the 1.30pm kick-offs!

Shane Long of Southampton (left) rises up to scores their second goal at St James' Park

Long celebrates his goal having come off the bench for the Saints

15:07

Arsenal 0-2 West Ham United

Well Giroud and Tomkins are back on the field as West Ham make their second change, sending on Kevin Nolan for Reece Oxford for the final 11 minutes. Solid debut from the 16-year-old.

15:05

Arsenal 0-2 West Ham United

The good news is Giroud is back to his feet but surely he will have to go off now, with concussion a serous concern here.

Tomkins is also departing it seems. Play goes on with both teams down to 10.

15:03

Arsenal 0-2 West Ham United

Worrying scenes at the Emirates Stadium. James Tomkins ad Giroud clash heads battling for a header inside the West Ham box, and the incident sees the Arsenal striker knocked out and motionless.

He is now receiving treatment on the pitch - hopefully he will be ok.

Arsenal's Olivier Giroud (left) and Mesut Ozil stand dejected after West Ham United score their second goal

15:01

Newcastle United 2-1 Southampton

Newcastle still lead but they have an injury concern as Vurnon Anita is taken off following an injury. Cheick Tiote is on to replace him.

14:56

Arsenal 0-2 West Ham United

Another change for Arsenal and it's a biggie as Alexis Sanchez replaces Mathieu Debuchy. Is there going to be anyone left in the Gunners' defence as this game goes on?

14:55

Newcastle United 2-1 Southampton

Speaking of trying to get back into the game, that takes us to Newcastle where Shane Long has replaced Jay Rodriguez for Southampton.

Jose Fonte nods over a corner from Dusan Tadic over the Newcastle bar.

14:53

Arsenal 0-2 West Ham United

There are still 25 minutes left at the Emirates Stadium, so plenty of time for Arsenal to get back into this.

The Gunners win a free-kick on the left but Cazorla's cross into the box is headed straight at Adrian by Giroud.

Mauro Zarate scores a goal to double West Ham's lead over Arsenal

Zarate celebrates his goal for West Ham in front of the Hammers travelling support

14:51

Arsenal 0-2 West Ham United

Sensing that Arsenal are about to go hell and leather for three goals to grab a win, Slaven Bilic turns to the bench and sends on Matt Jarvis for Zarate. The Hammers introduce fresh legs on the wing in attack rather than bolster up the defence.

14:49

Arsenal 0-2 West Ham United

The anchor is up now for Arsenal. Arsene Wenger reacts immediately by sending on Theo Walcott for Coquelin. Prepare for an Arsenal onslaught on the West Ham goal...

14:44

GOAL! Arsenal 0-2 WEST HAM UNITED

Well this is unbelievable! I'm stunned. Arsenal are sloppy all over as first Oxlade-Chamberlain is so easily barged off the ball by Mauro Zarate, before the forward's low drive towards the near post bottom corner sees Cech get nowhere near it. That's not what you pay over £10m for in a keeper.

Before that Giroud was wasteful with a low shot from the edge of the box which Adrian easily stopped, Cech take note...

14:41

From Sportsmail's Matt Barlow at the Emirates Stadium

'Cazorla started second half in the centre. Ramsey wide left. Still not quite right. Nearly an hour into the season and the natives are starting to get restless at the Emirates.'

14:37

GOAL! NEWCASTLE UNITED 2-1 Southampton

Big fan of this - what a header! Cisse's chipped ball down the right releases Gabriel Obertan, whose cross is wonderfully glanced in by Georginio Wijnaldum - on his debut too! Welcome to Tyneside, son.

Georgina Wijnaldum of Newcastle United scores their second goal at the start of the second half

Wijnaldum celebrates scoring on his Newcastle United debut

14:37

Newcastle United 1-1 Southampton

What a save from Krul! The Newcastle keeper adjusts his body magnificently to deny Maya Yoshida's downward header from a Steven Davis free-kick.

14:35

Newcastle United 1-1 Southampton

We have also restarted at St James' Park where Southampton have made a change, Cuco Martina coming on for Cedric Soares.

14:33

SECOND HALF: Away we go again - Arsenal were out early for this period...

West Ham United boss Slaven Bilic looks on from the Emirates Stadium touchline

'Even before the goal, something wasn’t quite clicking for Arsenal in this first half. There are flashes there, of the swift passing and moving and fluid play, but it is not all operating like clockwork yet.

'Arsene Wenger has spent some time on the touchline, hands on hips, surveying it all. He has got some work to do at half time.'

14:19

HALF-TIME: Newcastle United 1-1 Southampton

14:18

HALF-TIME: Arsenal 0-1 West Ham United

14:14

GOAL! NEWCASTLE UNITED 1-1 Southampton

Just the response Steve McClaren wanted! A looping cross from the left dips over Stekelenburg and allows Papiss Cisse to head a simple header home from two yards.

Papiss Cisse of Newcastle United scored the equalising goal from just a couple of yards out

A Petr Cech error helps West Ham into the lead! This was the last thing I thought I would see today!

The Hammers win a free-kick 35 yards out and as Payet swings the set-piece into the box, Cech comes and misses with the punch with Cheikhou Kouyate beating the keeper to the ball to head home into an empty net.

Petr Cech of Arsenal fails to punch clear the ball as Cheikhou Kouyate of West Ham United heads in the opening goal

Cheikhou Kouyate of West Ham United celebrates scoring the opening goal at the Emirates Stadium

14:13

Arsenal 0-0 West Ham United

Still the Arsenal attacks flow. Ramsey squares for Cazorla on the edge of the box, whose instant pass into the box finds Olivier Giroud, only for his shot to be saved by the advancing Adrian.

The Arsenal striker was flagged offside, but replays suggest he was rather unfortunate with that.

14:11

From Sportsmail's Craig Hope at St James' Park

'It took Steve McClaren 27 minutes to vacate his vantage in the stands. He's now in the dugout with his side needing a bit of direction in the wake of Pelle's opener.'

14:10

Arsenal 0-0 West Ham United

West ham have held firm so far but Arsenal are knocking on the door. Cazorla works his magic on the left after cutting inside, before he squares for Ramsey whose low drive across goal from 25 yards flies wide.

14:08

From OptaJoe

2 - Pellè has scored only his 2nd Premier League goal away from St Mary's for Southampton (13 in total). Welcome.

Another penalty appeal for Newcastle is denied! Again it's a handball shout, with Jay Rodriguez's arm outstretched as from close range a Papiss Cisse header bounces off the Southampton striker.

It's too close to move his arm out the way of the ball, but should it have been raised that high?

Arsene Wenger, manager of Arsenal, reacts on the touchline

14:05

Arsenal 0-0 West Ham United

Top save from Adrian. The West Ham keeper has to react well to tip away an Aaron Ramsey strike which took a wicked deflection off Cresswell and was looping in until the Hammers stopper reached back to tip over.

14:00

Arsenal 0-0 West Ham United

What a run! Oxlade-Chamberlain runs nearly 70 yards down the right, skipping past the West Ham defence like they are not there (they may as well not be) before crossing to the far post for Cazorla, whose cushioned volley loops just over the crossbar.

13:56

GOAL! Newcastle United 0-1 SOUTHAMPTON

Not a good start for Mbemba on the pitch. Cedric Soares pumps a deep cross into the box and Graziano Pelle peels off the defender to head home into the bottom corner at the back post.

The Italian has hardly had a touch but he has punished a lapse in Toon defending. Tim Krul could have perhaps done better in goal too.

Graziano Pelle (right) celebrates opening the scoring for Southampton at Newcastle United

13:56

Newcastle United 0-0 Southampton

Strong penalty appeals for Newcastle, but the referee is having none of it as play is waved on after Maya Yoshida appears to bock a Fabricio Coloccini shot. The only debate is was the defender too close?

13:53

From Sportsmail's Sam Cunningham at the Emirates Stadium

'Applause for Alexis Sanchez from the Arsenal fans as he warms up on the touchline. He gives them a little wave. The Chilean is wearing the brightest pink boots I have ever seen.'

13:53

Arsenal 0-0 West Ham United

Wonderful play from Dimitri Payet to keep in an Aaron Cresswell pass on the byline, and he does even better to cross for Diafra Sakho, whose weak volley under pressure is comfortably gathered by Petr Cech.

13:50

From Sportsmail's Matt Barlow at the Emirates Stadium

'Arsenal are comfortable; but curious decision by Wenger to isolate Cazorla on the left.

'Cazorla has been the heartbeat of everything Arsenal have done well in 2015. On the left, it is more difficult for him to get in the game and leaves Coquelin and Ramsey to orchestrate play when neither of them do this as well as Cazorla.'

Santi Cazorla of Arsenal attempts to charge through half of West Ham's outfield players at the Emirates Stadium

13:49

Newcastle United 0-0 Southampton

Chances at both ends at St James' Park. Southampton have the better one as Cedric Soares' shot from point blank range inside the box is blocked clear by Tim Krul, while straight up the other end Papiss Cisse drills straight at Maarten Stekelennburg from 20 yards.

13:43

Arsenal 0-0 West Ham United

Oh so close to a stunning opener from Oxlade-Chamberlain! The forward swipes his foot across a volley from the edge of the box, with his powerful strike curling viciously just wide of the top corner.

13:41

From Sportsmail's Craig Hope at St James' Park

'You get the impression they're going to like Chancel Mbemba in these parts. He's just thundered through a 50-50 with Jay Rodriguez - emerging with the ball at his feet to equally thunderous applause.'

Massadio Haidara (right) of Newcastle United is tripped by Dusan Tadic of Southampton

13:40

Arsenal 0-0 West Ham United

So much for that good West Ham start. It's another Hammers yellow card as Angelo Ogbonna is booked for a foul on Alex Oxlade-Chamberlain. Mesut Ozil's free-kick deflects wide for a corner which Laurent Koscielny then nods over. It's all Arsenal now.

Arsenal's Aaron Ramsey and Francis Coquelin both look to win the ball for the Gunners

13:36

Arsenal 0-0 West Ham United

It takes just under five minutes for a first yellow card in the London derby as West Ham midfielder Mark Noble's slip costs him a yellow card as he is forced to chop down Francis Coquelin to prevent a counter attack.

13:33

Arsenal 0-0 West Ham United

I was expecting Arsenal to come out all guns blazing but its West Ham who have a spring in their step, winning an early corner. The Gunners though easily head clear at the near post.

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13:28

Players are out at the Emirates Stadium and St James' Park

From Sportsmail's Craig Hope at St James' Park:

'New season here at St James' Park but one thing which has not changed is the deafening PA system. It'll be a relief when the game gets started.

'The big talking point though is Steve McClaren's decision to pair Fabricio Coloccini and Chancel Mbemba at the heart of the defence. The duo have not started a single game between them this pre-season, let alone played together.

'It could be some test against a Saints frontline of Tadic, Mane, Rodriguez and Pelle.'

Georginio Wijnaldum and Aleksandar Mitrovic are on the Newcastle bench, but Mbemba will have to change out of that tux as he makes his Toon debut today.

12:55

Arsenal make two changes from the Community Shield win

In come Mathieu Debuchy and Olivier Giroud for Hector Bellerin and Theo Walcott. West Ham do start Reece Oxford who at 16-years-old and 237 days will be the seventh youngest player in Premier League history.

Newcastle's new signings Chancel Mbemba (nice tux) and Aleksandar Mitrovic have arrived at St James' Park, where ground staff are too applying the finishing touches around the ground, including polish the Newcastle badge. It really is a clean break on Tyneside this season....(sorry)

Chancel Mbemba of Newcastle United arrives at St James' Park prior to making his debut

Aleksandar Mitrovic of Newcastle United is also in line to make his Toon debut

Siem de Jong, injured for most of last season, will hope to impress this term for Newcastle

A groundsman at Newcastle cleans the club badge inside St James' Park

Ground staff apply the finishing touches on match day as sprinklers water the pitch at St James' Park

11:58

And the opening Premier League weekend rumbles on with a London derby

And by no means a cheap one. Arsenal will be looking to flex their muscles as title challengers this afternoon against a West Ham side who have already got their campaign off to a stumbling start after tumbling out of the Europa League in the qualifying rounds.

Can the Hammers bounce back at the Emirates Stadium?

It's not all about London though. In the North East, Newcastle United begin life under Steve McClaren against a Southampton side who are showing West Ham how it is done in the Europa League qualifying rounds.

Two top games are lined up this afternoon, and that's just the start of it. Welcome all to Sportsmail's live coverage of the 1.30pm kick-offs!

Emirates Stadium ground staff mark out the pitch before the Barclays Premier League match between Arsenal and West Ham United

An Arsenal groundsman repaints the pitch lines before the opening game of the season

Sprinklers were also watering the pitch behind the goal before the terraces opened

The London derby between Arsenal and West Ham United is set to take place under bright sunshine at the Emirates Stadium